A particulate measurement device is used in order to measure the number of particulates in liquid. Patent Literature 1 and Non-Patent Literature 1 disclose, as one type of a particulate measurement device, a device which performs detection of particles by making liquid flow into a transparent cell such as quartz and observing scattered light which is generated when the cell is irradiated with light.
Further, Patent Literature 2 discloses a counter which counts the number of bacteria by irradiating sample water containing fluorescently stained bacteria with excitation light and receiving fluorescence from the bacteria. In this counter, a jet stream is formed by the sample water discharged from a nozzle. Then, the jet stream is irradiated with light from an excitation light source, and fluorescence from within a water flow is received by a photodetector. The number of bacteria is determined based on a signal which is output from the photodetector.